Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.
1. A method for capturing sound using a headset having at least one earpiece, wherein a user's ear canal is closed by the earpiece, the earpiece including an external microphone and an internal microphone, wherein the internal microphone is positioned in or on an inside portion of the earpiece and the external microphone is positioned in or on an outside portion of the earpiece, and wherein the internal microphone is located in a chamber formed by the earpiece and an ear of the user, said method including steps of: (a) in the presence of sound including own voice content and noise, generating an external microphone signal indicative of the sound as captured by the external microphone, and generating an internal microphone signal indicative of the sound as captured by the internal microphone, where the own voice content is indicative of at least one vocal utterance of the user of the headset; and (b) performing noise reduction on the external microphone signal, including by filtering the internal microphone signal to generate a filtered signal indicative of at least some of the noise as captured by the external microphone, and generating a noise reduced signal indicative of the own voice content by subtracting the filtered signal from the external microphone signal, wherein the step of filtering the internal microphone signal to generate the filtered signal corresponds to application of a transfer function, InvP(z), to the internal microphone signal, wherein the transfer function, InvP(z), is equal to or at least substantially equal to an inverse of a transfer function, P(z), that represents filtering during transit through the earpiece to the internal microphone.
Acoustic capture and noise reduction technology for headsets. This invention relates to methods for capturing sound with a headset equipped with at least one earpiece that seals the user's ear canal. The earpiece incorporates both an external microphone positioned on the outer surface and an internal microphone situated within or on the inner surface. The internal microphone is located within a chamber formed by the earpiece and the user's ear. The method begins by simultaneously capturing sound using both microphones. The external microphone records ambient sound, which may include the user's own voice and background noise. The internal microphone records sound within the sealed ear canal, which is primarily influenced by ambient sound that has passed through the earpiece and the user's own voice resonating within the ear. Noise reduction is then performed on the signal from the external microphone. This involves filtering the internal microphone signal to create a filtered signal that represents a portion of the noise captured by the external microphone. This filtered signal is then subtracted from the external microphone signal, resulting in a noise-reduced signal that emphasizes the user's own voice content. The filtering of the internal microphone signal is achieved by applying a transfer function, InvP(z), which is substantially the inverse of a transfer function, P(z), representing the acoustic path from the earpiece exterior to the internal microphone.
2. The method of claim 1 , wherein the step of filtering the internal microphone signal to generate the filtered signal corresponds to application of the transfer function, InvP(z), to the internal microphone signal, so that said filtered signal is the signal, InvP(z)M, where M is the internal microphone signal, InvP(z) is the inverse of the transfer function, P(z), Se is ambient sound, which is noise originating from one or more sources external to the user of the headset, as sensed and captured by the external microphone, whereby said ambient sound, Se, is distinct from and does not include the own voice content, and P(z)Se is a signal at least substantially equal to the ambient sound, Se, as sensed and captured by the internal microphone, whereby the signal P(z)Se corresponds to the ambient sound, Se, after undergoing filtering by the transfer function P(z) during transit through the earpiece to the internal microphone.
This invention relates to noise cancellation in headsets, specifically addressing the challenge of isolating ambient sound captured by an internal microphone from the user's own voice. The method involves filtering the internal microphone signal using an inverse transfer function, InvP(z), to remove the ambient sound component. The internal microphone captures a mixed signal containing both the user's voice and ambient noise, which has been altered by the earpiece's acoustic transfer function, P(z). By applying the inverse transfer function, InvP(z), to the internal microphone signal, the ambient noise component is effectively canceled, yielding a filtered signal that isolates the user's voice. The ambient noise, Se, is separately captured by an external microphone and is distinct from the user's voice. The transfer function P(z) represents how the ambient noise is modified as it travels through the earpiece to the internal microphone. This filtering step ensures that the filtered signal, InvP(z)M, accurately represents the user's voice without the interference of ambient noise. The method enhances voice clarity in communication devices by effectively separating the desired voice signal from external noise.
3. The method of claim 2 , wherein step (b) includes a step of performing equalization on the noise reduced signal to reduce distortion of the own voice content indicated by the noise reduced signal, thereby generating an equalized noise reduced signal, wherein the step of performing equalization on the noise reduced signal corresponds to application of a transfer function, E(z), to the noise reduced signal, so that said equalized noise reduced signal is the signal, E(z)X, where X is the noise reduced signal, E(z) is at least substantially equal to P(z)InvT(z), InvT(z) is the inverse of a transfer function, T(z), and the transfer function, T(z), characterizes filtering of the own voice content due to transmission through a portion of the user's body to the internal microphone.
This invention relates to audio processing for improving the clarity of a user's voice captured by an internal microphone, such as in a bone conduction or in-ear microphone system. The problem addressed is the distortion of the user's voice caused by transmission through the user's body, which alters the frequency response before reaching the microphone. The invention describes a method to reduce noise and then apply equalization to compensate for the distortion introduced by the body's transmission characteristics. The method involves first reducing noise from the captured signal to isolate the user's voice. After noise reduction, an equalization step is applied to correct the distortion caused by the body's filtering effect. The equalization uses a transfer function, E(z), derived from the inverse of the body's transfer function, T(z), which models how the voice signal is altered during transmission. The equalized signal, E(z)X, where X is the noise-reduced signal, restores the original voice characteristics by counteracting the distortion introduced by the body's transmission path. This ensures the output signal more accurately represents the user's voice as it was originally produced.
4. The method of claim 3 , wherein the transfer function, E(z), is a stable approximation to P(z)InvT(z).
A system and method for signal processing involves approximating a transfer function to improve stability in control systems or signal filtering applications. The transfer function, denoted as E(z), is designed as a stable approximation of the inverse of a product of two other transfer functions, P(z) and InvT(z). This approximation addresses instability issues that may arise when directly inverting or combining these functions, particularly in scenarios where P(z) and InvT(z) individually or in combination exhibit unstable behavior. The approximation ensures that the resulting transfer function remains stable while maintaining desired system performance characteristics. This approach is useful in control systems, communication systems, and signal processing applications where stability is critical. The method involves selecting or designing E(z) such that it closely matches the behavior of P(z)InvT(z) while avoiding poles or other characteristics that would lead to instability. The approximation can be implemented using various techniques, including polynomial fitting, rational approximation, or optimization-based methods, depending on the specific requirements of the application. The resulting stable transfer function can then be used in feedback control loops, equalization, or other signal processing tasks where stability is a primary concern.
5. The method of claim 1 , wherein step (b) includes a step of performing equalization on the noise reduced signal to reduce distortion of the own voice content indicated by the noise reduced signal, thereby generating an equalized noise reduced signal.
This invention relates to audio signal processing, specifically to methods for enhancing voice clarity in noisy environments. The problem addressed is the degradation of voice signals due to background noise, which can distort the user's own voice content and reduce communication quality. The method involves processing an audio signal containing both voice and noise components. First, noise reduction is applied to the audio signal to suppress background noise, producing a noise-reduced signal. This step may involve spectral subtraction, adaptive filtering, or other noise suppression techniques. Next, equalization is performed on the noise-reduced signal to correct distortions in the voice content. The equalization step adjusts the frequency response of the signal to compensate for any spectral imbalances introduced by the noise reduction process or inherent in the original signal. This generates an equalized noise-reduced signal with improved voice clarity and naturalness. The equalization may be adaptive, dynamically adjusting based on the characteristics of the noise or voice content. The method ensures that the processed signal retains the integrity of the original voice while minimizing the impact of noise and distortion. This approach is particularly useful in applications such as teleconferencing, voice assistants, and hearing aids, where clear voice communication is critical.
6. The method of claim 1 , wherein step (b) includes performing residual noise reduction on the equalized noise reduced signal.
This invention relates to signal processing techniques for reducing noise in audio or communication signals. The problem addressed is the presence of residual noise in signals after initial noise reduction steps, which can degrade audio quality or communication clarity. The invention provides a method to further enhance noise reduction by applying an additional residual noise reduction step to an already equalized and noise-reduced signal. The method involves first obtaining a noisy input signal, which may be an audio or communication signal corrupted by background noise. The signal undergoes an initial noise reduction process to remove a portion of the noise. This is followed by an equalization step to adjust the frequency response of the noise-reduced signal, ensuring balanced audio quality. The key improvement is the subsequent application of residual noise reduction to the equalized signal, which targets and further suppresses any remaining noise components that were not fully addressed in the initial noise reduction stage. This additional step ensures a cleaner output signal with improved signal-to-noise ratio and perceptual quality. The residual noise reduction may involve advanced techniques such as spectral subtraction, adaptive filtering, or machine learning-based noise suppression, tailored to the specific characteristics of the residual noise. The method is particularly useful in applications like voice communication, audio recording, and speech recognition, where minimizing noise is critical for performance.
7. The method of claim 6 , wherein the noise includes coherent noise and incoherent noise, subtraction of the filtered signal from the external microphone signal in step (b) removes most of the coherent noise from the external microphone signal, the noise reduced signal and the equalized noise reduced signal are indicative of at least some of the incoherent noise, and the residual noise reduction is performed so as to remove at least some of the incoherent noise from the equalized noise reduced signal.
This invention relates to noise reduction techniques for audio signals, specifically addressing the challenge of mitigating both coherent and incoherent noise in audio processing systems. The method involves capturing an external microphone signal containing noise and a desired audio signal. The noise is categorized into coherent noise, which is correlated with a known reference signal, and incoherent noise, which is uncorrelated. The method first filters the external microphone signal to isolate the coherent noise component. By subtracting this filtered signal from the original external microphone signal, most of the coherent noise is removed, resulting in a noise-reduced signal. This noise-reduced signal, along with an equalized version of it, is then analyzed to identify remaining incoherent noise. A residual noise reduction step is applied to further reduce the incoherent noise, enhancing the clarity of the desired audio signal. The technique ensures that both types of noise are effectively minimized, improving audio quality in environments with mixed noise sources. The method is particularly useful in applications such as speech recognition, communication devices, and audio recording systems where noise interference is problematic.
8. The method of claim 6 , also including a step of: performing own voice detection on at least one of the noise reduced signal, the equalized noise reduced signal, the external microphone signal, or the internal microphone signal to determine time segments of own voice activity, and wherein the step of performing residual noise reduction on the equalized noise reduced signal uses a noise estimate determined from at least one of the noise reduced signal, the equalized noise reduced signal, the external microphone signal, or the internal microphone signal at times between the time segments of own voice activity.
This invention relates to audio processing systems, specifically methods for improving voice communication quality by reducing noise and enhancing voice clarity. The problem addressed is the presence of background noise and residual noise in audio signals captured by microphones, which degrades voice communication quality. The invention provides a method to enhance voice signals by performing noise reduction, equalization, and residual noise reduction while dynamically adapting to the presence of the user's own voice. The method involves capturing audio signals from both an external microphone and an internal microphone. Noise reduction is applied to the internal microphone signal to produce a noise-reduced signal. This noise-reduced signal is then equalized to produce an equalized noise-reduced signal. The method further includes performing own voice detection on at least one of the noise-reduced signal, the equalized noise-reduced signal, the external microphone signal, or the internal microphone signal to identify time segments where the user is speaking. Residual noise reduction is then applied to the equalized noise-reduced signal using a noise estimate derived from the same signals during periods when the user is not speaking. This ensures that noise reduction is applied only during non-speech intervals, preserving voice clarity while minimizing residual noise. The system dynamically adjusts noise reduction parameters based on detected voice activity, improving overall audio quality in noisy environments.
9. The method of claim 8 , wherein the step of performing own voice detection includes steps of: comparing power of the noise reduced signal or the equalized noise reduced signal, and power of the external microphone signal, on a frame by frame basis; identifying each frame, of the noise reduced signal or the equalized noise reduced signal, whose power is much smaller than the power of a corresponding frame of the external microphone signal as an own-voice absent frame corresponding to a time segment other than a time segment of own voice activity; and identifying each frame, of the noise reduced signal or the equalized noise reduced signal, whose power is not much smaller than the power of the corresponding frame of the external microphone signal as an own-voice frame corresponding to a time segment of own voice activity.
This invention relates to voice processing systems, specifically methods for detecting the presence of a user's own voice in audio signals. The problem addressed is accurately distinguishing between a user's voice and background noise in noisy environments, which is critical for applications like voice recognition, communication devices, and hearing aids. The method involves analyzing audio signals captured by an external microphone and a noise-reduced or equalized version of the same signal. The process compares the power of these signals on a frame-by-frame basis. Frames where the power of the noise-reduced or equalized signal is significantly lower than the external microphone signal are classified as "own-voice absent," indicating no user speech. Conversely, frames where the power difference is minimal are classified as "own-voice present," indicating active speech. This approach improves voice detection accuracy by leveraging noise reduction techniques to isolate the user's voice from environmental noise. The method ensures reliable voice activity detection even in challenging acoustic conditions.
10. The method of claim 8 , wherein the step of performing own voice detection includes steps of: comparing levels of frequency components of time segments of the internal microphone signal and levels of frequency components of corresponding time segments of the external microphone signal in a low frequency range; determining that each time segment of the internal microphone signal and the external microphone signal in which the levels of the frequency components of the internal microphone signal are higher than the levels of the frequency components of the external microphone signal, in the low frequency range, is indicative of own voice activity; and determining that each time segment of the internal microphone signal and the external microphone signal in which the levels of the frequency components of the internal microphone signal are not higher than the levels of the frequency components of the external microphone signal, in the low frequency range, is not indicative of own voice activity.
The invention relates to a method for detecting a user's own voice in audio signals captured by internal and external microphones. The problem addressed is distinguishing the user's voice from ambient noise or other sounds in a communication device, such as a headset or hearing aid, to improve voice recognition or noise suppression. The method involves analyzing frequency components of audio signals from an internal microphone (e.g., worn close to the user's mouth) and an external microphone (e.g., exposed to ambient noise). Time segments of both signals are compared in a low-frequency range, where the user's voice typically dominates. If the internal microphone's signal has higher frequency component levels than the external microphone's signal in a given time segment, the segment is classified as containing the user's voice. Conversely, if the internal signal is not higher, the segment is classified as not containing the user's voice. This comparison helps isolate the user's speech from background noise, improving voice detection accuracy. The technique is particularly useful in noisy environments where distinguishing the user's voice from external sounds is challenging.
11. The method of claim 10 , wherein the low frequency range is a range from a frequency at least substantially equal to 100 Hz to a frequency at least substantially equal to 500 Hz.
This invention relates to signal processing, specifically to methods for analyzing or processing signals within a defined low-frequency range. The method involves identifying and extracting signal components that fall within a specific frequency band, which is critical for applications such as noise reduction, audio processing, or vibration analysis. The low-frequency range is precisely defined as spanning from at least 100 Hz to at least 500 Hz, ensuring that only relevant frequency components are isolated for further processing. This range selection is important for applications where low-frequency signals, such as those in audio systems or industrial machinery monitoring, need to be accurately captured or filtered. The method may include steps such as filtering, amplification, or modulation of the signal within this range to enhance or suppress specific frequency components. By focusing on this narrow band, the technique improves signal clarity, reduces interference, and enables more precise analysis or control of low-frequency phenomena. The approach is particularly useful in environments where low-frequency noise or vibrations must be managed, such as in audio engineering, structural health monitoring, or communication systems. The method ensures that only the most relevant frequency components are processed, improving efficiency and accuracy in signal analysis.
12. A headset, including: at least one earpiece including an external microphone positioned in or on an outside portion of the earpiece and an internal microphone positioned in or on an inside portion of the earpiece, wherein a user's ear canal is closed by the earpiece and the internal microphone is located in a chamber formed by the earpiece and an ear of the user, configured to operate in the presence of sound including own voice content and noise, to generate an external microphone signal indicative of the sound as captured by the external microphone, and to generate an internal microphone signal indicative of the sound as captured by the internal microphone, where the own voice content is indicative of at least one vocal utterance of the user of the headset; and an audio processing system coupled to receive the external microphone signal and the internal microphone signal, and configured to perform noise reduction on the external microphone signal and the internal microphone signal to generate a noise reduced signal indicative of the own voice content, including by: filtering the internal microphone signal to generate a filtered signal indicative of at least some of the noise as captured by the external microphone, and generating the noise reduced signal by subtracting the filtered signal from the external microphone signal, wherein the audio processing system is configured to filter the internal microphone signal to generate the filtered signal in a manner corresponding to application of a transfer function, InvP(z), to the internal microphone signal, wherein the transfer function, InvP(z), is equal to or at least substantially equal to an inverse of a transfer function, P(z), that represents filtering during transit through the earpiece to the internal microphone.
A headset includes at least one earpiece with an external microphone positioned on the outside and an internal microphone positioned on the inside. The earpiece seals the user's ear canal, creating a chamber where the internal microphone captures sound, including the user's voice and ambient noise. The external microphone captures sound from the environment. An audio processing system receives signals from both microphones and performs noise reduction. The system filters the internal microphone signal to isolate noise components, then subtracts this filtered signal from the external microphone signal to produce a noise-reduced output. The filtering process applies a transfer function, InvP(z), which is the inverse of the transfer function P(z) representing how sound is filtered as it travels through the earpiece to the internal microphone. This approach enhances voice clarity by suppressing background noise while preserving the user's vocal content. The system dynamically adjusts to varying noise conditions, ensuring effective noise reduction in real-time.
13. The headset of claim 12 , wherein the audio processing system is configured to filter the internal microphone signal to generate the filtered signal in a manner corresponding to application of the transfer function, InvP(z), to said internal microphone signal, so that said filtered signal is the signal, InvP(z)M, where M is the internal microphone signal, InvP(z) is the inverse of the transfer function, P(z), Se is ambient sound, which is noise originating from one or more sources external to the user of the headset, as sensed and captured by the external microphone, whereby said ambient sound, Se, is distinct from and does not include the own voice content, and P(z)Se is a signal at least substantially equal to the ambient sound, Se, as sensed and captured by the internal microphone, whereby the signal P(z)Se corresponds to the ambient sound, Se, after undergoing filtering by the transfer function P(z) during transit through the earpiece to the internal microphone.
This invention relates to noise cancellation in headsets, specifically addressing the challenge of isolating a user's voice from ambient noise captured by an internal microphone. The system includes an audio processing unit that filters the internal microphone signal using an inverse transfer function, InvP(z), to remove ambient noise. The internal microphone captures both the user's voice and external ambient noise, Se, which has passed through the earpiece and been modified by the transfer function P(z). By applying InvP(z) to the internal microphone signal, the system generates a filtered signal, InvP(z)M, where M is the original internal microphone signal. This filtering effectively cancels the ambient noise component, leaving the user's voice isolated. The external microphone captures the original ambient noise, Se, which is distinct from the user's voice. The transfer function P(z) represents how ambient noise is altered as it travels through the earpiece to the internal microphone. The inverse function, InvP(z), reverses this alteration, allowing the system to subtract the ambient noise from the internal microphone signal. This approach enhances voice clarity in noisy environments by accurately separating the user's voice from external sounds.
14. The headset of claim 12 , wherein the audio processing system includes an equalization subsystem coupled to receive the noise reduced signal and configured to perform equalization on said noise reduced signal to reduce distortion of the own voice content indicated by said noise reduced signal, thereby generating an equalized noise reduced signal.
This invention relates to audio processing in headsets, specifically addressing the challenge of maintaining clear voice communication while reducing background noise. The headset includes an audio processing system that processes audio signals to enhance voice clarity. The system first reduces ambient noise from the audio signal, producing a noise-reduced signal. This noise-reduced signal is then processed by an equalization subsystem, which applies equalization to correct distortions in the user's voice content. The equalization adjusts the frequency response of the noise-reduced signal to improve intelligibility and naturalness of the voice. The result is an equalized noise-reduced signal that preserves the user's voice while minimizing interference from background noise. This approach ensures that the transmitted audio is both clear and free from distortion, enhancing communication quality in noisy environments. The equalization subsystem dynamically adjusts based on the characteristics of the noise-reduced signal to optimize voice clarity.
15. The headset of claim 14 , wherein the audio processing system also includes a noise reduction subsystem coupled and configured to perform residual noise reduction on the equalized noise reduced signal.
This invention relates to audio processing systems for headsets, specifically addressing the challenge of improving audio quality by reducing noise in real-time. The headset includes an audio processing system that processes audio signals to enhance clarity and reduce unwanted noise. The system first applies noise reduction to an input audio signal, then equalizes the noise-reduced signal to adjust its frequency response. Additionally, the system includes a noise reduction subsystem that performs further residual noise reduction on the equalized signal. This secondary noise reduction step targets any remaining noise that persists after the initial noise reduction and equalization, ensuring a cleaner output. The combination of these steps—initial noise reduction, equalization, and residual noise reduction—enhances the overall audio quality by systematically addressing different types of noise and frequency imbalances. The invention is particularly useful in environments where background noise is significant, such as in communication devices, virtual reality headsets, or professional audio equipment. By refining the signal at multiple stages, the system provides a more refined and pleasant listening experience.
16. An audio processing system for extracting own voice content captured by a microphone set of an earpiece of a headset, where the own voice content is indicative of at least one vocal utterance of a user of the headset and the microphone set includes an external microphone positioned in or on an outside portion of the earpiece and an internal microphone positioned in or on an inside portion of the earpiece, wherein the user's ear canal is closed by the earpiece and the internal microphone is located in a chamber formed by the earpiece and an ear of the user, said audio processing system including: at least one input coupled to receive an external microphone signal indicative of output of the external microphone and an internal microphone signal indicative of output of the internal microphone, where the external microphone signal and the internal microphone signal have been generated with the external microphone and the internal microphone in the presence of sound including noise and the own voice content, the external microphone signal is indicative of the sound as captured by the external microphone, and the internal microphone signal is indicative of the sound as captured by the internal microphone; and a noise cancellation subsystem coupled and configured to perform noise reduction on the external microphone signal and the internal microphone signal to generate a noise reduced signal indicative of the own voice content, including by: filtering the internal microphone signal to generate a filtered signal indicative of at least some of the noise as captured by the external microphone, and generating the noise reduced signal by subtracting the filtered signal from the external microphone signal, wherein the noise cancellation subsystem is configured to filter the internal microphone signal to generate the filtered signal in a manner corresponding to application of a transfer function, InvP(z), to the internal microphone signal, wherein the transfer function, InvP(z), is equal to or at least substantially equal to an inverse of a transfer function, P(z), that represents filtering during transit through the earpiece to the internal microphone.
This invention relates to audio processing systems designed to extract a user's own voice from audio captured by a headset microphone set, particularly in noisy environments. The system addresses the challenge of isolating the user's voice from ambient noise when the headset's earpiece seals the ear canal, creating a closed acoustic chamber. The microphone set includes an external microphone positioned outside the earpiece and an internal microphone inside the earpiece, within the sealed chamber. The system receives signals from both microphones, which capture a mix of the user's voice and environmental noise. A noise cancellation subsystem processes these signals to generate a noise-reduced output. The internal microphone signal is filtered to estimate the noise captured by the external microphone, and this filtered signal is subtracted from the external microphone signal to isolate the user's voice. The filtering applies a transfer function, InvP(z), which approximates the inverse of the transfer function P(z) representing the acoustic path from the external environment to the internal microphone. This approach enhances voice clarity by effectively canceling out ambient noise while preserving the user's vocal content.
17. The system of claim 16 , wherein the noise cancellation subsystem is configured to filter the internal microphone signal to generate the filtered signal in a manner corresponding to application of the transfer function, InvP(z), to said internal microphone signal, so that said filtered signal is the signal, InvP(z)M, where M is the internal microphone signal, InvP(z) is the inverse of the transfer function, P(z), Se is ambient sound, which is noise originating from one or more sources external to the user of the headset, as sensed and captured by the external microphone, whereby said ambient sound, Se, is distinct from and does not include the own voice content, and P(z)Se is a signal at least substantially equal to the ambient sound, Se, as sensed and captured by the internal microphone, whereby the signal P(z)Se corresponds to the ambient sound, Se, after undergoing filtering by the transfer function P(z) during transit through the earpiece to the internal microphone.
This invention relates to noise cancellation in headsets, specifically addressing the challenge of isolating a user's voice from ambient noise captured by internal microphones. The system includes a noise cancellation subsystem that processes signals from an internal microphone and an external microphone to filter out ambient noise. The subsystem applies an inverse transfer function, InvP(z), to the internal microphone signal (M) to generate a filtered signal, InvP(z)M. This filtered signal represents the ambient noise (Se) as it would be captured by the internal microphone, accounting for the transfer function P(z) that modifies the ambient sound during transit through the earpiece. The ambient noise (Se) originates from external sources and is distinct from the user's voice. By applying InvP(z), the system effectively reconstructs the ambient noise component in the internal microphone signal, allowing it to be subtracted or otherwise processed to enhance voice clarity. The transfer function P(z) models how ambient sound is altered by the earpiece's acoustic path, ensuring accurate noise cancellation. This approach improves voice communication quality by isolating the user's speech from external interference.
18. The system of claim 16 , also including: an equalization subsystem coupled to receive the noise reduced signal and configured to perform equalization on said noise reduced signal to reduce distortion of the own voice content indicated by said noise reduced signal, thereby generating an equalized noise reduced signal.
This invention relates to audio signal processing systems designed to enhance voice communication by reducing noise and distortion. The system is particularly useful in environments where background noise interferes with clear voice transmission, such as in telecommunication devices, hearing aids, or speech recognition systems. The core functionality involves a noise reduction subsystem that processes an input audio signal to suppress unwanted noise while preserving the integrity of the desired voice content. This noise-reduced signal is then further processed by an equalization subsystem, which applies equalization techniques to correct frequency imbalances and reduce distortion in the voice content. The equalization subsystem adjusts the frequency response of the noise-reduced signal to ensure that the output signal has a more natural and intelligible sound. The combined noise reduction and equalization processes improve the clarity and quality of the transmitted voice signal, making it easier for listeners to understand speech in noisy conditions. The system is adaptable to various applications where high-quality voice communication is critical.
19. The system of claim 18 , also including: a noise reduction subsystem coupled and configured to perform residual noise reduction on the equalized noise reduced signal.
A system for processing audio signals includes a noise reduction subsystem that performs residual noise reduction on an equalized noise-reduced signal. The system first captures an input audio signal containing both desired audio and unwanted noise. A noise estimation module analyzes the input signal to identify and characterize the noise components. A noise reduction module then applies noise reduction techniques to the input signal based on the noise estimation, producing a noise-reduced signal. An equalization module adjusts the frequency response of the noise-reduced signal to improve audio quality. The noise reduction subsystem further processes the equalized signal to remove any remaining residual noise, enhancing the clarity and fidelity of the output audio. This system is particularly useful in environments where background noise interferes with audio clarity, such as in communication devices, audio recording equipment, or speech recognition systems. The multi-stage noise reduction approach ensures that both initial and residual noise are minimized, resulting in a cleaner output signal.
20. A tangible, computer readable medium which stores, in a non-transitory manner, code for programming an audio processing system to perform processing on an external microphone signal indicative of output of an external microphone of an earpiece of a headset and an internal microphone signal indicative of output of an internal microphone of the earpiece, wherein the internal microphone is positioned in or on an inside portion of the earpiece and the external microphone is positioned in or on an outside portion of the earpiece, wherein a user's ear canal is closed by the earpiece and the internal microphone is located in a chamber formed by the earpiece and an ear of the user, and where the external microphone signal and the internal microphone signal have been generated with the external microphone and the internal microphone in the presence of sound including noise and own voice content, the external microphone signal is indicative of the sound as captured by the external microphone, the internal microphone signal is indicative of the sound as captured by the internal microphone, and the own voice content is indicative of at least one vocal utterance of the user of the headset, said processing including a step of: performing noise reduction on the external microphone signal, including by filtering the internal microphone signal to generate a filtered signal indicative of at least some of the noise as captured by the external microphone, and generating a noise reduced signal indicative of the own voice content by subtracting the filtered signal from the external microphone signal, wherein the step of filtering the internal microphone signal to generate the filtered signal corresponds to application of a transfer function, InvP(z), to the internal microphone signal, wherein the transfer function, InvP(z), is equal to or at least substantially equal to an inverse of a transfer function, P(z), that represents filtering during transit through the earpiece to the internal microphone.
This invention relates to audio processing systems for headsets, specifically addressing the challenge of isolating a user's voice from background noise in environments where the earpiece seals the ear canal. The system processes signals from two microphones: an external microphone on the outside of the earpiece and an internal microphone inside the earpiece, which captures sound within the sealed chamber formed by the earpiece and the user's ear. The external microphone captures both ambient noise and the user's voice, while the internal microphone primarily captures noise filtered through the earpiece structure. The system performs noise reduction by filtering the internal microphone signal to estimate the noise component present in the external microphone signal. This filtering applies a transfer function, InvP(z), which is the inverse of the transfer function P(z) representing how noise is altered as it passes through the earpiece to the internal microphone. The filtered signal, representing the estimated noise, is subtracted from the external microphone signal to produce a noise-reduced output that emphasizes the user's voice. This approach leverages the physical relationship between the microphones to improve voice clarity in noisy environments. The invention is implemented via code stored on a non-transitory computer-readable medium, enabling the audio processing system to execute the described noise reduction steps.
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March 10, 2020
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